There's a large stack of community software that was developed with funding from the DOE's SciDAC program. http://usqcd-software.github.io/ http://usqcd-softwa

There's a large stack of community software that was developed with funding from the DOE's SciDAC program. http://usqcd-software.github.io/ http://usqcd-software.github.io/ People use the stack in a variety of different ways---I'll describe my own usage. There's a message-passing abstraction layer, QMP, sitting over MPI or SMP or what have you (you can compile for your laptop for development purposes, for example). This keeps most of the later layers relatively architecture agnostic. Over that sits QDP, the data parallel library. Here's where the objects we discuss in quantum field theory are defined. We almost always work on regular lattices. QDP also contains things like "shove everybody one site over in the y direction" (for example). Finally, there's the physics/application layer, where the physics algorithms live. I am most familiar with chroma. QUDA is the GPU library and can talk to most application-layer libraries and has at least simple solvers for most major discretizations people want to use (it also has fancier solvers such as multigrid methods for some discretizations). Code in chroma by and large looks like physics equations, if you had a pain-in-the-ass pedantic student who didn't understand any abuse of notation. Chroma can be used as a library, so that for your particular project you can do nonstandard things while leveraging everything it can already do. Other physics layers include CPS, which grew out of the effort at Columbia with QCDSP/QCDOC, MILC (really optimized code for staggered fermions), and others. The USQCD stack isn't the only one. Another modern lattice field theory package is grid, developed by a tight collaboration between intel and University of Edinburgh https://github.com/paboyle/grid https://github.com/paboyle/grid. There's also openQCD http://luscher.web.cern.ch/luscher/openQCD/ http://luscher.web.cern.ch/luscher/openQCD/